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At least 55 records · Page 3Linked to original sources
PubMed1975

[The influence of anticipation of pain on heart and respiratory rates and on the pain reflex in man].

A study was undertaken in man to determine the effects of anticipation of pain on the heart rate, respiratory rhythm and nociceptive component of the flexor reflex. Two groups of subjects were used: a group of trained subjects and a group of naive ones. A warning, given 10 min before the delivery of the painful stimulation, made the naive subjects anxious while the trained ones remained relaxed. The latter subjects showed a steady heart rate and respiratory frequency as well as a steady level in the nociceptive reflex threshold for the duration of the experiment. Two kinds of responses were exhibited by the naive subjects: one group showed increased heart rate and respiratory frequency as well as an initial increase in the reflex threshold; the other group showed decreased heart rate, increased respiratory frequency and an initial decrease in the reflex threshold. In each sub-group of the naive subjects, the time course of the reflex threshold showed a progressive evolution towards the threshold level of the trained subjects with a time course of 30--40 min.

Anxiety↗
PubMed1997

Respiratory rate and body mass in the first three years of life. The working party on respiratory rate.

The correlation between respiratory rate and body mass in the first three years of life was examined in 635 infants and children, aged between 15 days and 3.5 years. Assessments were made during quiet sleep and when awake and calm. Their body weight (2.8-20.5 kg) was measured at the same time. Respiratory rate decreased exponentially with increasing body weight. After log transformation of the data, a linear correlation was found between log(respiratory rate) and log(body weight) both during the sleeping and the wakeful states. For each body weight group, boys had about a 6.5% higher respiratory rate than girls, but both the boys' and the girls' lines were parallel. The slope of the line was -0.43 during sleep and -0.41 during wakefulness, indicating that the respiratory rate: body weight ratio is not a constant in either state, and that it decreases as body weight increases. Adding age to the model did not significantly increase the precision of the fitting. A simple equation of the form respiratory rate = a body weight(b), can accurately describe the decrease in respiratory rate with growth. Smaller (hence younger) infants and children have a higher respiratory rate per unit body weight than larger (hence older) children.

Body Weight↗
PubMed2006

Age related reference ranges of respiratory rate and heart rate for children in South Africa.

BACKGROUND: The authors have recently presented reference ranges for heart rate and respiratory rate in healthy resting schoolchildren, aged 4-16 years, in the United Kingdom. There are no similar ranges for children in the developing world. AIMS: To undertake a study in Cape Town, South Africa, to establish whether the UK ranges may be applied to socioeconomically disadvantaged groups. METHODS: Data on 346 children in a township school were recorded; their height, weight, heart rate, and respiratory rate were compared to the UK ranges. RESULTS: The two groups plotted closely together by height and weight on the UK 90 growth reference charts. There was no difference in heart rate between the two groups, and a difference of 0.46 breathes per minutes in respiratory rate, which is not felt to be of clinical significance. CONCLUSION: The reference rages of heart and respiratory rate derived in the UK may be applied to children in developing world situations.

Adolescent↗
PubMedDate not supplied

Increasing staff awareness of respiratory rate significance.

Respiratory rate is a significant predictor of critical illness and an important part of early-warning scoring. After an audit of patient records revealed a low incidence of respiratory-rate recording, a hospital-wide education programme was set up to raise awareness and improve critical care skills among ward staff. A repeat audit showed significant improvement in recording rates and identified new areas for training.

Attitude of Health Personnel↗
PubMed2003

Effects of epidural opioid analgesics on heart rate, arterial blood pressure, respiratory rate, body temperature, and behavior in horses.

Heart rate, arterial blood pressures, respiratory rate, body temperature, and central nervous system excitement were compared before and after epidural administration of morphine (0.1 mg/kg), butorphanol (0.08 mg/kg), alfentanil (0.02 mg/kg), tramadol (1.0 mg/kg), the k-opioid agonist U50488H (0.08 mg/kg), or sterile water using an incomplete Latin square crossover design in five conscious adult horses. Treatments were administered into the first intercoccygeal epidural space. Significant (P <.05) reductions in respiratory rate were detected after epidural administration of morphine, alfentanil, U50488H, and sterile water. Additionally, significant (P <.05) head ptosis was observed within the first hour after administration of morphine, U50488H, and tramadol, but neither of these changes appeared to be of clinical significance. No treatment-related changes in motor activity or behavior were observed.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1980

Respiratory rate as an indicator of acute respiratory dysfunction.

To assess respiratory rate as an indicator of acute respiratory dysfunction, we studied 58 consecutive patients four times daily during the postoperative period. Of 825 measurements of respiratory rate, 726 (89%) were normal (24/min or less). Elevations in respiratory rate without respiratory dysfunction were found in only 4% of all measurements. Patients without lung disease had a mean respiratory rate of 18 +/- 4/min, while patients with an abnormal respiratory rate and respiratory dysfunction had a mean of 27 +/- 5/min. Our study demonstrates that respiratory rate, if carefully measured, is a sensitive and reasonably specific marker of acute respiratory dysfunction.

Abdomen↗
PubMed2003

The effects of tidal volume and respiratory rate on oxygenation and respiratory mechanics during laparoscopy in morbidly obese patients.

UNLABELLED: Morbidly obese (MO) patients undergoing laparoscopy have lower PaO(2) compared with normal-weight (NW) patients. We hypothesized that increases in tidal volume (V(T)) or respiratory rate (RR) would improve oxygenation. All measurements were performed at: 1) baseline: V(T) 600-700 mL and 10 breaths/min, 2) double V(T): V(T) 1200-1400 mL and 10 breaths/min, and 3) double rate: V(T) 600-700 mL and 20 breaths/min. We calculated static respiratory system compliance (Cst,rs) and inspiratory resistance (RI,rs). End-tidal CO(2) was measured with a mass spectrometer, and PaO(2) and PaCO(2) with a continuous blood gas monitor. Supine anesthetized MO patients had 29% lower Cst,rs than the NW patients (P < 0.05). Positioning patients head-up or head-down before pneumoperitoneum did not significantly affect Cst,rs in either group (P = 0.8). Doubling the V(T), but not RR, increased Cst,rs in both groups. Pneumoperitoneum caused large decreases in Cst,rs in both groups (both P < 0.001). During pneumoperitoneum, changing the body position, V(T), or RR did not further affect Cst,rs in either group (P > 0.7). Before pneumoperitoneum, RI,rs was higher in the MO patients compared with the NW patients regardless of body position (P = 0.01). Doubling either RR or V(T) before pneumoperitoneum did not change RI,rs in either group. After pneumoperitoneum, RI,rs increased in both the head-down and head-up positions (P < 0.05), but not in the supine position. Regardless of the conditions studied, alveolar-arterial difference in oxygen tension was always significantly higher in MO patients (P < 0.05). The alveolar-arterial difference in oxygen tension was not affected by body position, pneumoperitoneum, or the mode of ventilation. Arterial oxygenation during laparoscopy was affected only by body weight and could not be improved by increasing either the V(T) or RR. IMPLICATIONS: Morbid obesity decreases arterial oxygenation and respiratory system compliance. During laparoscopy, arterial oxygenation is affected only by the patient's body weight. Increases in tidal volume or respiratory rate do not improve arterial oxygenation.

Adult↗
PubMed2002

Mitochondrial respiratory rates and activities of respiratory chain complexes correlate linearly with heteroplasmy of deleted mtDNA without threshold and independently of deletion size.

To clarify the importance of deleted protein and tRNA genes on the impairment of mitochondrial function, we performed a quantitative analysis of biochemical, genetic and morphological findings in skeletal muscles of 16 patients with single deletions and 5 patients with multiple deletions of mtDNA. Clinically, all patients showed chronic progressive external ophthalmoplegia (CPEO). The size of deletions varied between 2.5 and 9 kb, and heteroplasmy between 31% and 94%. In patients with single deletions, the citrate synthase (CS) activity was nearly doubled. Decreased ratios of pyruvate- and succinate-dependent respiration were detected in fibers of all patients in comparison to controls. Inverse and linear correlations without thresholds were established between heteroplasmy and (i) CS referenced activities of the complexes of respiratory chain, (ii) CS referenced maximal respiratory rates, (iii) and cytochrome-c-oxidase (COX) negative fibers. In patients with single and multiple deletions, all respiratory chain complexes as well as the respiratory rates were decreased to a similar extent. All changes detected in patients with single deletions were independent of deletion size. In one patient, only genes of ND5, ND4L as well as tRNA(Leu(CUN)), tRNA(Ser(AGY)), and tRNA(His) were deleted. The pronounced decrease in COX activity in this patient points to the high pathological impact of these missing tRNA genes. The activity of nuclear encoded SDH was also significantly decreased in patients, but to a lesser extent. This is an indication of secondary disturbances of mitochondria at CPEO. In conclusion, we have shown that different deletions cause mitochondrial impairments of the same phenotype correlating with heteroplasmy. The missing threshold at the level of mitochondrial function seems to be characteristic for large-scale deletions were tRNA and protein genes are deleted.

Citrate (si)-Synthase↗
PubMed1984

Increasing cardiac rate by tracking the respiratory rate.

The rate responsive pacemaker using respiratory rate as a sensor was implanted in 22 patients, 19 patients for ventricular pacing and three for atrial pacing. The level of exercise achieved with this system was consistently higher than with a fixed ventricular pacing rate. In addition, no special chemical or mechanical sensors are required; the sensor itself is simple, long-lasting, and energy efficient. Thus, this system adapts easily to the individual patient.

Adolescent↗
PubMed2004

Increased tidal volume variability in children is a better marker of opioid-induced respiratory depression than decreased respiratory rate.

OBJECTIVE: During opioid administration, decreasing respiratory rate is typically used as a predictor of respiratory depression. Prior to opioid-induced apnea, progressively irregular breathing patterns have been noticed. We hypothesize that opioid administration to children will increase tidal volume variability (TV(var)) and that this will be a better predictor of respiratory depression than a decrease in respiratory rate. METHODS: We recruited 32 children aged 2-8 years scheduled to undergo surgery. During spontaneous ventilation, flow rates and respiratory rates were continuously recorded, while remifentanil was infused at stepwise increasing doses each lasting 10 min. The infusion was continued until the patient showed signs of respiratory depression. Flow data from each dose was used to calculate tidal volumes, from which TV(var) was calculated. The respiratory rate and TV(var) during the last (D(last)), second to last (D-2), and third to last (D-3), administered doses were compared to those during baseline (fourth to last dose). We chose a threshold of TV(var) increase and compared it to a decrease in respiratory rate below 10 breaths per min as predictors of respiratory depression. RESULTS: Compared to baseline, the TV(var) increased by 336% and 668% during D(-2) and D(last), respectively, whereas respiratory rate decreased by 14.3%, 31.7%, and 55.5% during D(-3), D(-2), and D(last), respectively. A threshold increase in TV(var) of 150% over baseline correctly predicted respiratory depression in 41% of patients, compared to a drop in respiratory rate correctly predicting 22% of patients. CONCLUSIONS: TV(var) increases as children approach opioid-induced respiratory depression. This is a more useful predictor of respiratory depression than a fall in respiratory rate because the TV(var) increase is 10 times the drop in respiratory rate. A TV(var) increase also correctly predicts respiratory depression twice as often as decreased respiratory rate and is independent of age-related alterations in physiologic respiratory rates.

Analgesics, Opioid↗
PubMed1983

Respiratory rate as a determinant of optimal pacing rate.

Efforts have been made to utilize biologic parameters for determining optimal cardiac pacing rates. In this study of 67 patients, a significant relationship between heart rate and respiratory rate was observed during dynamic exercise. A system using a radiofrequency activator to modify pacing rate is described. Eleven patients have received VVI pacemakers with a similar implanted radio receiver coil. In two patients the fully automatic system has been successfully implanted. The experience with respiratory rate as a determinant of pacing rate is encouraging.

Aged↗
PubMed2003

The effects of specific respiratory rates on heart rate and heart rate variability.

In this study respiratory rates of 3, 4, 6, 8, 10, 12, and 14 breaths per minute were employed to investigate the effects of these rates on heart rate variability (HRV). Data were collected 16 times at each respiratory rate on 3 female volunteers, and 12 times on 2 female volunteers. Although mean heart rates did not differ among these respiratory rates, respiratory-induced trough heart rates at 4 and 6 breaths per minute were significantly lower than those at 14 breaths per minute. Slower respiratory rates usually produced higher amplitudes of HRV than did faster respiratory rates. However, the highest amplitudes were at 4 breaths per minute. HRV amplitude decreased at 3 breaths per minute. The results are interpreted as reflecting the possible effects of the slow rate of acetylcholine metabolism and the effect of negative resonance at 3 cycles per minute.

Adult↗
PubMedDate not supplied

Respiratory rates in emergency department patients.

The respiratory rate is a sensitive and nonspecific indicator of respiratory dysfunction. Establishing a "normal" respiratory rate has mainly been arbitrary. This study evaluated "normal" respiratory rates in 110 emergency department patients. The mean respiratory rate was 20.1 (+/- 4.0). Women had a more rapid respiratory rate 20.9 (+/- 3.9) than men 19.4 (+/- 4.0) (p less than .04). Smokers had a higher respiratory rate 20.5 (+/- 4.0) than nonsmokers 19.3 (+/- 4.0), but this was not statistically significant (P = 0.124). It was also noted that the respiratory rate measured by the nurse was almost always different from that measured by the medical student (P less than 0.0001). Based on a review of the literature concerning what constitutes a "normal" respiratory rate, we conclude that the "normal" respiratory rate may be higher than that suggested in the medical literature.

Adult↗